Can you make a heater blow hotter?

[Chris B.]

Thanks!

 

[Vikas]

What is your temperature gauge showing? It should be just slightly under the half mark i.e. some where between 1/4 and 1/2. It should reach there within 2-3 miles of city driving at 50F ambient temperature.

If it is taking lot longer to reach there or if it is hovering at 1/4 mark, you have a bad thermostat.

 

[Chris B.]

It hits the half way point fast! It is on the wavy lines.

 

[Vikas]

Once it has reached the steady temperature (just slightly under the half mark) put the heat on the max high and put the back of your palm on the floor vent. If you can keep it there for 30 seconds, your car is not giving you enough heat. If it becomes uncomfortable to hold it there, your car has ample heat.

Frankly, unless you are sure there is a problem, don't let dealer go on fishing expedition. Have somebody else drive and see if they agree with the problem.

- Vikas

 

[Tegger]

Well, I used my infrared thermometer today. It gave me the below results, on a vehicle which has more than adequate heat in any weather.

(Thermostat is a 78C OE Honda, fully-open at 194F)

Upper rad hose outlet (the hottest spot in the system): 205F
Thermostat housing: 180F
Floor outlets for the heater (fan on full-blast): 145F.

I'd just arrived from a 2-1/2 hour drive, so the engine was about as warmed-up as I could expect.

 

[Vikas]

Tegger,

Do you climate control system on that vehicle? 145F at floor vent sounds way too hot for an electronic system.

 

[JamesBond]

I'm not sure how your heater control valve is controlled but on my civic there is a cable that runs from a motor under the dash to a heater control valve under the hood on one of the heater hoses. I was getting a little warm air out of the vents even when the manual temp was set all the way cool. I took the cable end off of the valve and was able to move the heater control valve to a fully closed position. Then adjusted the cable slack by moving the cable in the clip that holds it to the firewall.

Maybe your heater control valve is not fully opening and your cable needs to be adjusted on either the motor end or the heater valve end.

Or maybe its a new car and the cooling system isn't fully bled and you have an air bubble to work out.(Any gurgling under the dash when you start it with the heat on?) Try leaving the heat on and parking up hill for a few days.

 

[Tegger]

Originally Posted By: Vikas
Tegger,

Do you climate control system on that vehicle? 145F at floor vent sounds way too hot for an electronic system.

It's a mechanical system, but the control method is not important. If you've set the thing to maximum heat, highest fan-speed, all the air to the floor, and with the engine fully warmed-up, the vent temperature ought to be very close to what I measured.

In the region of the heater core, away from the vents, I actually saw temperatures even closer to the thermostat-housing temperature, or around 160.

 

[Vikas]

OK, that makes sense. I was thinking that automatic climate control would like to maintain the set temperature by blowing the same temperature air. But that is incorrect. 90F is less than a warm body temperature!

 

[Tegger]

Originally Posted By: Vikas
90F is less than a warm body temperature!

What you get out of the vents is nowhere near what reaches your body, even at the feet.

There is a huge amount of heat-loss into the ambient air, into the mass of the dash, through the floor, through the glass and roof, etc. This is why even 145F takes what seems like forever to make the car feel comfortable in the middle of winter.

 

[Vikas]

Do they have multiple temp sensors on automatic climate control? And is the logic similar to home thermostat?

 

[TFB1]

Originally Posted By: Chris B.
I set it to "Hi" which is like 89 or 90 degrees. I also had it set so that full air was blowing at the driver and the blower on hi.
I drove about 20 miles at 75mph and it was hot enough by the time I got home but still not as hot as my other cars get.


Generally outlet temp will not be as warm with blower on high as with it at a lower speed... If reducing speed doesn't help, there is possibly a issue with the blend door adjustment or it's seal... If there is a notable improvement at lower blower speed, either the coolant isn't up to temp or is a heater core issue...

 

[Chris B.]

How do you get to the blend door? Is it hard to get at? I don't want my dash to be taken apart.